Centrifuge for clarifying and standardizing milk



A Sept. 17, 1940.

S. H. HALL CENTRIFUGIFOR CLARIFYING ANI) STADARDIZING MILKv Uriginal Filed July?, 1938 Patented Sept. 17, 1940 CENTRIFUGE FOR CLARIFYING AND i STANDARDIZING MILK Selden IL Hall, Poughkeepsie, N. Y., assignor to The De Laval Separator Company, New York, N. Y., a corporation of New Jersey original application July 7. 193s, semi No.

217,891. Divided ana this applicati@ Max, 1.7,

premium for all fat content above 31/2% until the average of the milk they receive is often Well above 4%. At the same timeptheir competitors are putting them at a disadvantage by buying and paying for only milk that averages but a little above the legal 31/2% f-at requirement.

A very large' portion of the market milk is now centrifugally clarified to remove sediment and the object of my invention is to, while clarifying Il the milk, remove therefrom a large proportion of the fat in excess of the 31/% legal standard.

In an application filed by mie July 7, 1938, Serial No. 217,891, of which this application is a division, I disclose a process of treating whole milk to reduce its butter fat content to a predetermined percentage. In this process a minor part of the whole milk is centrifuged to separate milk relatively rich in butter fat from milk relatively poor in butter fat, which may be desig- 25.nated respectively as cream and skim milk. The

skim milk is then added to the majon (unskimmed)A part of the whole milk and the mixture subjected to centrifugal clarification, thereby producing a whole milk having precisely the characteristics of the original whole milk and differing therefrom only in that it has a predetermined reduced percentage of butter fat.

This process requires no novel operating devices for its executiombut merely a new arrangement of old operating devices. For example, the whole milk may be divided into a major stream and a minor stream, the former going direct to a clarifier of conventional type and-the latter going to a separator of conventional type. From the separator the skim milk from which the cream has been separated may be conveyed to the major stream; and the-mixture of unskimmed and skimmed milk conveyed to a clarier of conventional type having a single outlet, wherein the whole milk isy clarified and from which 'it is delivered. I

While the process can thus be practiced by the described new arrangement of old elements, I have designed a single centrifuge in which the whole process may be practiced in a manner f more simple, rapid and economical than by a newset-up of old elements. Such novel centrifuge comprises a bowl having a comparatively large clarifying compartiment provided'with a single outlet and a comparatively small separating compartment provided with separate outlets for the cream and skim milk, the skim milk outlet opening into theclarifying compartment; and a feed element for whole milk whose fat content it is desired to reduce which delivers a I minor proportion of the whole milk directly into the separating compartment and a major portion of the whole milk directly into the clarifying compartment. The latter thus receives for clarification both a relatively large volume of 10 l unskimmed whole milk and a relativelysmallV volume of skimmed whole milk. In the clarifying compartment the skim milk is thoroughly mixed with the whole milk and the mixture is delivered from the clarifying compartment as a l.

-homogeneous whole milk having all the characto the standard percentage. 25

Since the percentage of butter fat in excess of the standard percentage in different batches of whole milk is subject to considerable variation, means are provided to control the proportion of fat removed from the milk being clarified so that 30 the fat content of the skim milk delivered from the clarifying compartment will have the predetermined desired fat content. l

A preferred embodiment of the invention is shown in the drawing. Fig. l is a vertical sec- 35 tional view of a centrifuge embodying my invention. Fig. 2 is an enlargedv sectional view of a detail of Fig. 1.

II is a hollow spindle which supports and drives the bowl and through which and holes I3 .40 whole milk enters passages I4 in the under side of the disc carrier I5. The disc carrier isl provided with a shoulder I6 against which a disc I1, imperforate except for the center hole that ts around the stem of the disc carrier, fits 45. tightly. Below the disc Il there are a number of skimming discs I8 having distributing holes I9 with which passages 2D, branching loff from the passage Il, communicate.

From the inner edges of these discs a channel 50 ZI leads into, and upward through, the stem of the kdisc carrier I5 to a stationary tube 2'2 that continues to the outside of the machine Above the disc I1 there is a plurality of clarifying discs 23, only a few of which are shown, Il

the inner edges of which communicate with grooves 24 leading to the bowl outlet tube 25, revolving inside the seal 26, and the stationary discharge tube 21, While their outer edges openl to the peripheral space 28 with which the passages I4 communicate. I

The bowl has the usual shell 29 and top 30 held together by a coupling ring 3l.

' Whole milk whose fat content is to be reduced is fed through the spindle II and holes I3 to the heavier than the milk is separated out, then upward through the grooves 24 and tube 25 to the discharge tube 21.

Different expedients may be adopted to control the rate of discharge of the butter fat; in other words, to control the proportion of butter fat removed from the milk being clarified. One expedient is to control the back pressure on the cream discharged from the separating compartment. This may be effected by a control `valve 32, which may be of the type illustrated in the Hapgood Patent No. 2,145,544, issued January 31, 1939.

Alternately, the back pressure at the clarified milk outlet 21 may be varied by means of a throttle valve 33 on' discharge tube 21. 'I'his valve may be essentially like valve 32, that is,-

a valve that will vary the resistance to flow of skim milk from the separating compartment to the clarifying compartment. Or the size of the whole milk passages 20, or of passage I4 may be varied by means of exchangeable bushings 34, shown in both Figs. 1 and 2 as applied to passages 20, or otherwise. These expedients, or either of them, may also be adopted in combination with variation in back pressure at the cream outlet 22, which latter expedient, however, will alone give the desired control.

It should be understood that the described combined centrifugal separator and clarifier does not contemplate subjecting the entire volume of the whole milk successively to separation and clarication, since this would require a centrifuge of impracticably large size In a centrifuge invoivf ing my invention, since only a small percentage of the whole milk need be subjected to centrifugal separation, 'the separating compartment may be of such relatively Very small size as to involve a bowl substantially no larger than the ordinary standard clarifying bowl.

What Iclaim and desire to protect by Letters Patent is: 1

1. The combination in a centrifugal machine for separating and clarifying milk, a bowl having a relatively large clarifying compartment and a relatively small separating compartment, the latter having a Whole milk inlet, a skim milk outlet and an outlet adapted to deliver separated cream to an independent locus, the former having a whole milk inlet anda skim milk inlet communicating with the skim milk outlet of the separating compartment, and means to control the rate ofdischarge of the butter fat.

having a relatively large clarifying compartment l cating with its peripheral zone and with the clarifying compartment and thus adapted to deliver its heavy separated constituent to the clarifying compartment and the other outlet communicating with its central zone and thus adapted to Aseparately deliver a concentrated light component and means to control the rate of discharge of said concentrate.

3. A centrifugal machine comprising a bowl provided with two parallel centrifuging compartments, one being of relatively large dimensions having an inlet for a major portionof the liquid being treated and adapted to remove heavy solids therefrom and having a single outlet through which such liquid is discharged without separation, and the other of relatively small dimensions having an inlet for a minor portion of the nquid being treated and adapted to concentrate the lighter constituent and provided with two outlets through one of which the concentrate is separately discharged and through the other of which the heavier constituent is conveyed to the large compartment and therein clarified and discharged with the said major portion ofthe treated liquid.

4. A combined centrifugal separating and clarifying bowl having a relatively large clarifying compartment, a relatively small separating compartment, means to feed whole milk to the bowl and to deliver a larger'part thereof to the clarifying compartment and a smaller part thereof to the separating compartment, and means to deliver separated skim milk from the separating compartment to the entrance to the clarifying compartment, the separating compartment having an independent discharge for separated cream.

5. A combined centrifugal separator and clarifier for clarifying the whole milk while removing therefrom `a comparatively small proportionl of cream to thereby produce whole milk of standardized cream content, which comprises a centrifugal bowl having a relatively large clarifying compart-v ment' and a relatively small separating compartment, a feed channel for whole milk communicating with both compartments, a cream outlet from the smaller compartment, a skim milk outlet from the smaller compartment communicating with the larger compartment Aand a clarified milk outlet from the larger compartment. 6. A combined centrifugal separator and clariler for clarifying the whole milk While removing therefrom a comparatively small proportion of cream to thereby produce whole milk of' stand# ardized cream content, which comprises a centrifugal bowl having a relatively large clarifying compartment provided with a single outlet for y clarified milk and a relatively small separating compartment provided with separate-outlets for cream and skim milk, means to feed whole milk to both compartments and other means'to convey the skim milk separated in the smaller compartment to the larger compartment, whereby Whole milk of superstandard cream content ,may lbe standardized and clarified and the excess cream separatedvtherefrom in a single centrifuge.

7. A combined centrifugal separator and clari- 2. A centrifugal machine comprising a bowler for clarifying the whole milk while removing therefrom a part of the cream to thereby produce whole milk having the characteristics of the original whole milk but different therefrom onlyin its reduced cream content, which comprises a centrifugal bowl having a clarifying compartment and a separating compartment, a. feed channel for whole milk having two outlets, one directly opening into the clarifying compartment and the other directly opening into the separating compartment, to thereby feed to both compartments unskimmed -whole milk, a cream outlet from the separating compartment, a skim 'milk outlet from the separatingcom'partment to the clarifying compartment, and a clarified milk outlet from the' clarifying compartment.

8. A combinedcentrifugal separator and clarifier for clarifying the whole milk while removing therefrom a part of the cream to thereby producev whole milk of a reduced cream content, which comprises a centrifugal bowl having a clarifying compartment and a separating compartment, a feed channel for Whole milk having two outlets, one directly opening into the clarifying compartment and the other directly opening into the separating compartment, to thereby feed to both compartments unskimmed whole milk, a cream outlet from the separating compartment, the clarifying compartment occupying the entire bowl space except that occupied by the separating compartment, which is of smaller diameter than the bowl, the peripheral part of the separating compartment having a free opening into the greater diameter part of the bowl surrounding the separating compartment, the clarifying coml partment thus receiving for clarification whole milk which has not been subjected ,to separation and milk from which cream has been skimmed and which in the clarifying compartment mixes with the unskimmed whole milk to therein produce a clarified whole milk of reduced fat concomprises a centrifugal bowl having a clarifying compartment and aseparating compartment, a feed channel for Whole milk having two outlets,

one opening directly inte the clarifying compart-l ment and the other opening directly into the separating compartment whereby whole milk is fed to both compartments, a skim milk outlet from the separating compartment to the clarifying compartment adjacent to the entrance end there to for whole milk, an independent cream outlet from the'separating compartment and means to control the quantity of cream discharged therefrom.

SELDEN H. HALL. 

